The present invention relates generally to an improved pneumatic spreader system for distribution of particulate material or pulverulent solids upon the soil, and more particularly to a system for achieving such distribution which is less prone to clogging, and which achieves a more uniform distribution of solids through booms of varying lengths within a given distributor. Pressurized pneumatic systems for the distribution of particulate solids are known, and have been used for such purposes in the past, however the systems currently in use suffer from the disadvantage of occasional clogging of particulate solids within the distribution tube, or from uneven discharge of solids through the distributor system.
Agricultural techniques require the utilization of soil treating agents to either encourage, discourage, destroy, or inhibit plant growth. Such agents may generally be characterized as crop treating chemicals, and include such materials as nutrients such as fertilizers, and pesticides such as insecticides and pre-emergent or post-emergent plant growth inhibitors. In other words, the term "crop treating chemical" is used in a comprehensive sense to incorporate those various ingredients utilized in agriculture to treat either the soil, plants, or insects. Active materials used for treatment are commonly found in one of three forms, either water soluble, water wettable, or in particulate solid form. In connection with the present invention, particulate solids or granular materials are of interest, with the system of the present invention being particularly adapted for use in connection with the distribution of such materials onto the soil or other surfaces being treated.
In the treatment of agricultural fields and crops through spreading of an active treating ingredient, the efficiency of the treatment operation may be enhanced if the load to be carried is reduced. Therefore, the utilization of dry particulate solids will substantially reduce the load requirement, inasmuch as water or other treatment medium or treatment vehicle is not required. The utilization of pressurized pneumatic systems will normally eliminate the need for utilization of water, and with pneumatic systems normally utilizing a compressor in lieu of a liquid pressure source for delivery of the treating ingredient.
One common problem encountered with pressurized pneumatic systems for distribution of particulate solids or granular materials is that of uniformity of distribution. One factor leading up to lack of uniformity of distribution is a tendency for the granular materials to become lodged in the distribution system, thereby clogging or partially clogging a portion of the system. Such an event will, of course, impede normal air flow through the system. The pressurized pneumatic systems normally employ a plurality of elongated hollow delivery booms, with these booms being of predetermined and differing lengths, and extending laterally outwardly of the supporting vehicle. By extending the length of individual elongated delivery booms on either side of the vehicle, the area of coverage may be correspondingly increased. However, as boom length increases, problems with clogging, material build-up, and the resulting lack of uniformity of distribution have been found to increase proportionately. The features of the present invention have been found to reduce the tendency to clog, and thus enhance the uniformity of distribution of particulate solids from the system and onto the soil, with the system having been found to decrease material build up in certain portions of the system, particularly portions of the delivery booms. Conventional systems have been found to experience clogging and material build up, particularly at the point where the granular materials are being introduced into the flow of air. The features of the present invention have been found desirable for improving the performance of systems using elongated hollow discharge or delivery booms.